Prioritizing environmental risk at the regional scale by a GIS aided technique. The Copperbelt Province (Zambia) case study

To achieve satisfactory results in an environmental risk assessment procedure, mostly oriented to the safety of human health, a significant weight should be given to the possible exposure pathways and to the effective amount of exposed population. The Zambian Copperbelt Province, widely polluted by heavy metals due its mineralisation and long history of mining district,was chosen as a study area to develop and test a Geographical Information System (GIS) aided technique to prioritise risk at the regional scale. The distribution of metals in top- and bottom-soil was used to assess the contamination degree of the whole region. For this purpose, two specific exposure pathways were selected as the most relevant in themigration process of contaminants from source to human receptors in relation to the impact of different land uses in the risk assessment procedure: (1) soil/dust ingestion and (2) food ingestion. Population was introduced as a key variable for prioritisation of environmental risk. Further, a simple method to assign a priority score to contaminated landwas introduced to assist environmental professionals in the decisionmaking process and management of environmental risk at a regional scale without wasting resources and with the best cost–benefit ratio.